1. Field of the Invention
This invention is related to the field of integrated circuits and, more particularly, to interconnect within and/or between integrated circuits.
2. Description of the Related Art
Integrated circuits in a system, or various circuitry within an integrated circuit, typically have a need to communicate with each other. In many cases, communicators in the system/integrated circuit may communicate through various addresses in a memory map. That is, various communicators are assigned addresses within the memory map, and reads/writes to the addresses are used to communicate. Typically, such communicators use read/write transactions transmitted over an interconnect between the communicators.
For example, it is common to have an address bus over which the address, command, and other transaction information is transmitted to initiate a transaction. Additionally, a data bus may be used to transmit data corresponding to the transaction, if any. If cache coherency is implemented for the transactions, a response interface may be provided for maintaining the coherency states according to the coherency scheme implemented by the communicators. The bandwidth of the address bus and the data bus is somewhat limited, since only one address transfer can be transmitted on the address bus and only one data transfer can be transmitted on the data bus at a time. If two or more transfers could be done in parallel, the bus structure does not permit the parallelism. Additionally, buses tend to have high power consumption, as each communicator is coupled to the buses and presents a capacitive load to the driver of the bus.
Another interconnect that is often used is referred to as a crossbar. A crossbar typically permits each transmitting communicator to communicate with any receiving communicator, and any other transmitting communicator to communicate with any other receiving communicator, in parallel. However, the circuitry required in the crossbar to permit any set of concurrent connections between transmitters and receivers often leads to high power consumption.